Oscillograph recorder trace blanker apparatus

ABSTRACT

Electromechanical apparatus for blanking galvanometer traces and which can be used to advantage in high-speed computer data systems which include multi-channel oscilloscope recorders. A galvanometer is positioned symmetrically between two non-magnetic flat plates which are parallel to the galvanometer reference beam. The two plates are spaced apart a distance sufficient to allow the galvanometer reference beam to be deflected a selectively predetermined amount in each direction from the center of the galvanometer during unblanked operation. During blanked operation, electrical circuitry, which can be actuated locally or remotely, removes normal excitation from the galvanometer and energizes its with a blanking signal which deflects the reference beam onto one of the two plates to block it or shield it from the oscillograph recorder.

[ Oct. 31, 1972 [.54] OSCILLOGRAPH RECORDER TRACE BLANKER APPARATUS Primary Examiner-Joseph W. Hartary AttorneyR. S. Sciascia et al.

[57] ABSTRACT Electromechanical apparatus for blanking galvanometer traces and which can be used to advantage in highspeed computer data systems which include multichannel oscilloscope recorders. A galvanometer is positioned symmetrically between two non-magnetic flat plates which are parallel to the galvanometer reference beam. The two plates are spaced apart a distance sufficient to .allow the galvanometer reference beam to be deflected a selectively predetermined amount in each direction from the center of the galvanometer during unblanked operation. During blanked operation, electrical circuitry, which can be actuated locally or remotely, removes normal excitation from the galvanometer and energizes its with a blanking signal which deflects the reference beam onto one of the two plates to block it or shield it from the oscillograph recorder.

4 Claims, 3 Drawing Figures [72] Inventors: Richard R. Taylor; Frank A.

MacKay, both of Riverside, Calif.

[73]. Assignee: The United States of America as represented by the Secretary of the Navy [22] Filed: Nov. 24, 1971 [21] Appl.No.: 201,694

[52] U.S.Cl ..346/109 [51] Int. Cl. ..G01d 15/14 [58] Field of Search ..346/l09; 324/97 [56] References Cited I UNITED STATES PATENTS 2,467,950 4/1949 Thompson ..346/l09X 2,946,643 7/1960 Hutchison et al ..346/l09 X 3,374,485 3/1968 Gemrner ..346/23 3,422,444 l/l969 Stauffer ..346/l09 REFERENCE BEAM\ I BLANKED BEAM l \i \\'\REFLEGTED BEAM 22* LIGHT SOURCE 1 RECORDER -24 P'ATENTEDumm m2 13102002 sum 1 or 2 l2 14) 42 l2 l2 f 7 l0) FIG. 1

| v I fREFLECTEDBEAM REFERENCE BEAM\: I

SOURCE RECORDER 24 FlG. INVENTOR."

RICHARD R. TAYLOR FRANK A. MACKAY.

IBLANKING v SIGNAL SOURCE l ovnc Y 36-O V I REMOTE CONTROL SOURCE INVENTOR. RICHARD RT TAYLOR BY FRANK A. MACKAY v arzcoimsa rascr: nrsurraa I APPARATUS a, "aacxoaouivporriremvmvrron Currently, oscillographrecordershave multi-channel data recording capabilities in the order of 50 or more oscrrrocarmr channels. Obviously, it is impractical'andunwise touse that many channels in most applications since "that much data cannot be recorded"effectively'onconventional 12-inch recording paper. Consequently only the channels actually required should be utilized inany given'application and the others should beunblanked. The present invention comprises novel galvanometer blanking apparatus which can be manually or automatically controlled as by a computer .toselect only those V prises a plurality of non-magnetic flat plates 12 which Agalvanometer14.

are positioned in a parallel manner with respect to-each o'ther'and which are supported upon a common base member-20. I I a K It should be appreciated that although only seven plates are shown in FIG. 1, as many plates as, desired could be used'within the scope of the inventive concept. v

I which is shownin simplified form ispositioned symmetrically between each pair of ad-v jacent plates which are preferably black. Only one galvanometer is thus illustrated to simplify the description of the blanking device sincethe description would be 5 "identical for any other channel comprisin'gitwo' advchannels whose output is desiredto be recorded simul-- taneously and to blank out all the otherchannels.

SUMMARY or THE INVENTION A galvanometer trace blanke'r for multi-channel oscillograph recorders. and for use in automatic, computer-controlled systems-is-disclosed. The apparatus comprises a mechanical light shield for the galvanometer'reference beam and a'defle'cted beam position controller. The light shield includes a plurality of non-magnetie, flat plates-which are positioned and supported upon a common base member in a parallel relationship with respect to each other. Each galvanometer is symk metrically positioned between two adjacent plates which are parallel'to the galvanometer reference beam. The deflected beam position controller, inresponse to jacentplates and a galvanometer positioned between thetwo plates. v 1 a v V The galvanometer l4 comprises a conventional galvan-ometer which for purposes of illustration is shown in simplified formas consisting of a coil 16 having a rotatable mirror 18mounted thereon.

FIG. 2 represents a top view of the galvanometer 14 and its two" corresponding plates. As can'b'e seen, the galvanometer 14 is positioned symmetrically between the two plates 12 which are parallel tothe incoming galvanometer-reference beam from the light source 22.

ln normal, unblanked galvanometer operation, the

reference beam is focused upon the mirror 18:\ vhich is attached above the coil 16. The coil isexcited bya signal whose-magnitude isto be measured to thereby create a magnetic field about the coil which interacts local-or automatic ac'tuation,' energizes every galvanomete'rto be blanked" to thereby position the deflected beam behind the light shield to block itfrom the" recording device. The blanking excitation is removed by local or automatic excitation of v the deflected. beam 'position controllerto return the galdetailed description of the invention when considered inconjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG; 1 represents a front view of the preferred embodiment of the novel galvanometer trace blanking ap-- paratus which embraces the present inventive concept;

FIG. 2 represents a top view of one data channel of the apparatus of FIG. 1; and,

FIG. 3 represents a simplified electrical schematic of I trace is effectively blanked. Thus, any selectively with a permanent magnetic field in the galvanorneter. The interaction causes the coilto rotate an amount proportional to the strength of the signal.

The impinging reference beam is therebyirefle'cted from the mirror 18 an angular-amount equal to the rotation of the coil. The beam is reflected, from the mirroronto a scale'or recorder 24 which isa distance away, As the mirror turns, the reflected beam travels across the scale'or recording paper in the oscillograph recorder 24. a I

It is apparent from an examination of FIG. 2, that the reflected beam will not be reflected towards I the recorder if the coil rotates an amount sufficient to reflect the beam at either plate 12 which thereby function as light shields to block the beam from reaching the recorder 24. When this condition occurs, the galvanometer l4 predetermined number of galvanometers' can be blanked or unblanked in a multi-charinel oscil lograph recorder as required by a particular application.

The electrical circuit shown in simplified form in FIG. 3 can .be used to accomplish the above coil movement and subsequent galvanometer blanking. The cir cuit essentially comprises a double-pole, double-throw relay 26, a single-pole switch 28, a DC power supply the galvanorneter deflected beam position controller of 30, and a resistor 32. It should be understood that such the novel apparatus disclosed herein.

DESCRIPTION OF THE PREFERRED I EMBODIMENT FIG. 1 represents a front view of the mechanical unit "10 of the electromechanical galvanometer trace blanking circuit'to be disclosed herein. The unit 10 comalthough the input terminals 34. The relay 26 is energized so" that, as shown in FIG. 3, the input signal iscoupled directly to thegalvanometer coil 16 through the con-- tacts b-b' as previously indicated.

' The switch 28 is closed whereby the indicator lamp 38 indicates'whether the galvanometer is unblankedior blanked. The unblanked circuit is completed by the remote control source 40 through the terminals 36. If

'local control is used, the terminals 36 are shorted.

ln blanked operation, the relay circuit 26 is opened by a signal from the remote control source 40 or by opening switch 28 if local control is used. The relay coil is thereby de-energized and the contacts are switched to the q-a' position of FIG. 3. I

In thiscondition, the galvanometer coil 16 receives its energization from the DC power supply 30 through the resistor 32 The magnitudeof the blanking signal can be selectively adjusted to reflect the reference beam-into the blankingplates or light shields 12 as discussed above. The value of the resistor 32 is selected in accordance with the particular type of galvanometer being used. 1 v

Thus it can be seen that a new and novel blanking circuit for galvanometers and oscillograph recorders has been disclosed. Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood thatlwithin the scope of the appended claims the invention may be practiced otherwise than as specifically described. What is claimed is:

t 1. In galvanometer devices wherein a rotatable coil is deflected an amount proportional to the strength of a signal being measured and wherein a mirror is fastened rigidly to said coil to thereby reflect a reference beam onto a recording device to measure said strength, apparatus for blanking the reflected beam from said recording device comprising:

light shield means consisting of two non-magnetic, flat plates disposed and supported upon a common base member; said galvanometer device being disposed and supported between said two plates and said reference beam being parallel to said two plates;

said two plates being spaced apart a selectively predetermined distance-whereby said reference beam can be reflected between said two plates over a selectively predetermined deflection range; first switch means for applying said signal being measured to said galvanometer device during unblanked operation; a DC blanking voltagesource; g second switch means for removing said signal from said galvanometer device and for simultaneously applying a DC blanking voltage from said source thereto to reflect said reference beam onto one of said two plates. p 2. The apparatus of claim 1 further including means for indicating whether-said galvanometer device is unblanked or blanked. t v

3. The apparatus of claim 1 wherein said second switch means includes control means responsive to general-purpose computercommands.

4. ln'an oscillograph recorder having a plurality of galvanometers wherein a reference beam is reflected onto said recorder as a signal trace, apparatus for automatically blanking any of said galvanometers comprisiight shield means consisting of a plurality of nonmagnetic, flat plates positioned in a parallel manner and spaced apart a selectively predeter mined distance with respect to each and supported a DC voltage thereto to thereby reflect said reference beam onto one of said plates and thereby block it from reaching said recorder. 

1. In galvanometer devices wherein a rotatable coil is deflected an amount proportional to the strength of a signal being measured and wherein a mirror is fastened rigidly to said coil to thereby reflect a reference beam onto a recording device to measure said strength, apparatus for blanking the reflected beam from said recording device comprising: light shield means consisting of two non-magnetic, flat plates disposed and supported upon a common base member; said galvanometer device being disposed and supported between said two plates and said reference beam being parallel to said two plates; said two plates being spaced apart a selectively predetermined distance whereby said reference beam can be reflected between said two plates over a selectively predetermined deflection range; first switch means for applying said signal being measured to said galvanometer device during unblanked operation; a DC blanking voltage source; second switch means for removing said signal from said galvanometer device and for simultaneously applying a DC blanking voltage from said source thereto to reflect said reference beam onto one of said two plates.
 2. The apparatus of claim 1 further including means for indicating whether said galvanometer device is unblanked or blanked.
 3. The apparatus of claim 1 wherein said second switch means includes control means responsive to general-purpose computer commands.
 4. In an oscillograph recorder having a plurality of galvanometers wherein a reference beam is reflected onto said recorder as a signal trace, apparatus for automatically blanking any of said galvanometers comprising: light shield means consisting of a plurality of non-magnetic, flat plates positioned in a parallel manner and spaced apart a selectively predetermined distance with respect to each and supported upon a common base member; each of said galvanometers being positioned symmetrically between two adjacent plates; said two plates being positioned in a parallel manner with respect to said reference beams; first switch means for coupling signals to be measured to said galvanometer; second switch means for removing said signals from said galvanometer and for simultaneously coupling a DC voltage thereto to thereby reflect said reference beam onto one of said plates and thereby block it from reaching said recorder. 